Table II.
Patient characteristics according to reported annual family income
| Subject characteristics | <$50,000/yr (n = 128) |
>$50,000/yr (n = 218) |
p-value |
|---|---|---|---|
|
| |||
| Demographics | |||
|
| |||
| Age at onset | 6.5 (3.9, 10.1) N = 124 |
5.4 (3.4, 8.7) N = 216 |
0.13 |
|
| |||
| Female | 90/128 (70.3%) | 153/218 (70.2%) | 0.98 |
|
| |||
| Time to Diagnosis (months) | 4.9 (2.0, 12.1) N = 122 |
4.3 (2.0, 10.1) N = 216 |
0.28 |
|
| |||
| Race | |||
| White | 84 (65.6%) | 193 (88.5%) | <0.01 |
| Black | 32 (25.0%) | 11 (5.1%) | |
| Minority, non-Black | 12 (9.4%) | 14 (6.4%) | |
|
| |||
| Patient characteristics | |||
|
| |||
| Lipodystrophy | 6/127 (4.7%) | 9/217 (4.2%) | 0.80 |
|
| |||
| Calcinosis | 23/123 (18.7%) | 23/215 (10.7%) | 0.04 |
|
| |||
| ANA | 61/97 (62.9%) | 122/181 (67.4%) | 0.45 |
|
| |||
| Treatments | |||
|
| |||
| IV/Pulse corticosteroids | 73/121 (60.3%) | 130/199 (65.3%) | 0.10 |
|
| |||
| Oral corticosteroids | 118/122 (96.7%) | 197/202 (97.5%) | 0.12 |
|
| |||
| DMARDS/non-biologic DMARDS | 120/128 (93.8%) | 199/218 (91.3%) | 0.41 |
|
| |||
| Cytotoxic therapy1 | 3/119 (2.5%) | 1/196 (0.5%) | 0.12 |
|
| |||
| Biologics | 61/128 (47.7%) | 86/218 (39.5%) | 0.14 |
|
| |||
| IVIG | 55/128 (43.0%) | 83/217 (38.5%) | 0.20 |
|
| |||
| Disease activity | |||
|
| |||
| CHAQ2 | 0.38 (0, 1.00) N = 125 |
0 (0, 0.38) N = 215 |
<0.01 |
|
| |||
| Patient global | 3 (1, 5) N = 127 |
1 (0, 3) N = 214 |
<0.01 |
|
| |||
| Physician global | 1 (0, 3) N = 125 |
1 (0, 2) N = 207 |
0.02 |
|
| |||
| Weakness3 (moderate/severe) | 13/126 (10.3%) | 19/218 (8.7%) | 0.03 |
|
| |||
| Rash (facial erythema) | 38/126 (30.2%) | 65/217 (30.0%) | 0.97 |
|
| |||
| Gottron | 59/127 (46.5%) | 96/217 (44.2%) | 0.69 |
|
| |||
| CMAS4 | 49 (43, 52) N = 76 |
50 (45, 52) N = 141 |
0.44 |
|
| |||
| HRQOL5 | 3 (2, 3) N = 127 |
2 (1, 3) N = 213 |
<0.01 |
|
| |||
| ACR6 class (worst) | 0.05 | ||
| I | 17 (15.2%) | 44 (22.8%) | |
| II | 26 (23.2%) | 52 (26.9%) | |
| III | 30 (26.8%) | 43 (22.3%) | |
| IV | 39 (34.8%) | 54 (28.0%) | |
Parenthesis indicates percentage or interquartile 25–75% range (IQR). Chi square testing was used for comparison of counts; Kruskal-Wallis nonparametric testing was used for comparison of ordinal results. The p-values are for the comparisons between the two groups.
1
Cytotoxic drugs = cyclophosphamide (pulse or oral)
2
CHAQ = Childhood Health Assessment Questionnaire (higher is worse)
3
Weakness = moderate or severe proximal weakness by evaluating physician
4
CMAS = Childhood Myositis Assessment Scale (higher is better)
5
HRQOL = Health Related Quality of Life
6
ACR= American College of Rheumatology